[KarlInOhio]

http://biobug.org/scuba/scubatank/ calculates the energy in the compressed air in a scuba tank. So for a 230 bar 12L tank we have 230*12*450 Joules. 1,242,000 joules!

But gasoline has 34,200,000 Joules per liter, so a 12L scuba tank has the same amount of energy as 1.23 fluid ounces of gasoline. Woo-hoo!

[Reeses]

A compressed CO2 cartridge has much better performance than compressed air, but then it completely fails the CO2 emissions test.